This study aims to examine the tactical behavior, decision-making, and technical skills of young novice basketball players in small-sided games (SSGs) with different numerical configurations and court sizes. Participants were 16 novice male players aged between 11 and 15 years with no competitive experience. A total of 13 games were played, comprising nine SSG formats with numerical equality, superiority, and inferiority, in two court sizes: a full court (FC) and a half court (HC). In SSGs played in the FC, pass efficacy was significantly higher (p < 0.05) in 5 vs. 4 and 4 vs. 3 formats, while dribble efficacy was significantly higher (p < 0.05) in the 2 vs. 1 HC format. The 3 vs. 3 FC format showed greater (p < 0.05) shot efficacy. Reception efficacy was significantly higher (p < 0.05) in the 2 vs. 1 HC format, as well as rebound efficacy. However, appropriate passes were significantly lower (p < 0.05) in the 4 vs. 3 FC format. Dribble efficacy was significantly greater (p < 0.05) in the 2 vs. 1 HC format and appropriate shots were significantly greater (p < 0.05) in the 2 vs. 1 HC format. Regarding defensive and offensive technical-tactical actions, the 3 vs. 3 HC format presented significantly higher values (p < 0.05) of support, while ball marking was significantly greater (p < 0.05) in the 3 vs. 2 HC format. In conclusion, this study indicates that smaller (balanced and unbalanced) SSG formats tend to enhance the frequency, effectiveness, and appropriateness of attacking and defensive behaviors, particularly those involving direct actions.